


Short, Red, and Surly

by witchwrites



Category: Undertale (Video Game)
Genre: AFAB reader - Freeform, Dirty Talk, Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Flirting, Fluff, Love Bites, Other, Penis In Vagina Sex, Porn with Feelings, Smut, Soulmate-Identifying Marks, Underfell
Language: English
Status: In-Progress
Published: 2018-11-09
Updated: 2018-11-15
Packaged: 2019-08-21 05:43:19
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 8,186
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16570736
Author URL: https://archiveofourown.org/users/witchwrites/pseuds/witchwrites
Summary: During the most exciting work shift of your life, you get robbed at gunpoint and find out that you have a soulmate.This is a story about that, and the series of events that occur afterwards.





	1. Chapter 1

**Notes for the Chapter:**

> this is just a goofy little thing i’m doing for fun on the side when i need a break from my longer sans fic. please expect it to rapidly devolve into vignettes and smut
> 
> also apologies if the characters arent what you expect from this au its hard for me to tell what the canon is haha

“Stop scratching your mark, Sans!”

Sans grunts, jerking his hand away from his chest. “Sorry, boss.”

Papryus squints critically down at him. “It’s gross. We’re in public, Sans.”

“I said sorry,” Sans grumbles. “It’s just really itchy today.”

“You’ve been doing that a lot lately,” his brother comments, putting a hand on his hipbone and scrutinizing the small selection of pesticides in the gas station. “None of these packages make any sense. Why would I want anything that’s NOT extra strength?! Why do they only kill SOME insects?! I obviously want to kill EVERY insect!” 

Sans just grunts in agreement.

His soul mark has felt warm and itchy and uncomfortable ever since they moved to this neighborhood. It was worth it, because the rent was way cheaper than their last place, but it was still kind of a pain in his ass.

He knows that itch is supposed to mean his soulmate is nearby but he can’t be arsed to bother with it. What would be the point, anyway? In the Underground, the weaker soulmate was just something to be exploited by other monsters to hurt the stronger one. It’s not quite like that anymore, since the kid came and got them out of the mountain and changed everything and now monsters are learning to be  _ nice _ , but he still doesn’t understand why he’d seek his soulmate out. It’d just be a hassle.

Well, it’d be nice to stop the itching, maybe. But probably not worth it in the long run.

“Sans, STOP,” Papyrus shouts suddenly, smacking his hand away from his chest.

“Sorry,” Sans says again, shoving his hand back in his jacket pocket. Fuck, he didn’t even realize he was scratching that time. It’s just so damn itchy.

He looks at the pesticides and tries to focus on not scratching while Papyrus grumbles. He can overhear a conversation between two employees over by the entrance, but he doesn’t bother to look up.

“Hey, thanks for coming in early.”

“Yeah, no worries, I was hoping for some extra hours this week anyway.”

The door’s bell jangles as one of the employees leaves. Sans’s mark burns. He grunts.

“Ow, what the fuck,” he mutters, clutching at his shirt over his sternum where the mark is plastered on his bone.

Papyrus shoots him a funny look.

The bell jangles again.

“Hands up, right now!”

Sans can see Papyrus’s head jerk towards the commotion in his periphery before he looks himself.

Some human in a ski mask and a thick jacket is pointing a gun at the human employee behind the counter. The employee has their hands up, looking afraid and confused. The human briefly whirls around to point the gun at the two skeletons in the back of the store, but Sans is hardly paying attention to that. He’s looking down at the employee’s chest, where a little bit of skin is revealed by their unbuttoned polo shirt.

Where they have a weird splotch on their skin that looks just like the mark on his sternum.

He’s suddenly hit with an intense feeling of vertigo, stumbling forward and clutching at the shelf and knocking several items over to balance himself.

The human with the gun says something to him, shakes the gun in his direction. Sans doesn’t hear it. His head is all fuzzy and it feels like he has a fever. Everything looks weird and out of focus except for when he looks at that stupid, pretty employee behind the counter. 

Why do they look like that? Why are they so fucking pretty? What the fuck? What’s going on? Humans aren’t cute. Why does he think that human is cute?

They look at him with alarm -  _ please look at him, look at him some more, just not with that expression, please _ \- before jolting in surprise as the human with the gun turns back around and points it in their face. The employee nods frantically before doing something at the register and pulling out small stacks of money.

They look really scared. Sans doesn’t want them to be scared. They’re pretty even though their face is all twisted up in fear but they’d probably look better if they weren’t scared. They look soft, and nice. 

His soul is practically vibrating deep within him.

The human with the gun puts the weapon closer to the employee’s face.

What the fuck? That guy needs to leave them alone. What’s his problem? They’re giving him the money and everything.

He’s shouting something loudly, says he’ll shoot. Sans feels his brother’s hand on his back, hears him saying something.

But it’s too late. He’s not gonna let that guy with the gun hurt the pretty human behind the counter. He doesn’t even have to think about it. It’s pure instinct.

With a loud snarl, he raises his hand and jerks it upwards, sending a bone flying towards the guy with the gun. The guy turns at the noise and the bone goes sailing into his hand, knocking the gun out of it. It goes clattering over to the floor on the other side of the counter.

The employee and the man look at each other for a split second, and then the employee dives for the gun, popping back up and pointing it at the man.

He flees. The door jangles. 

The employee looks at Sans, dumbstruck, still holding the gun pointed at a man who isn’t there anymore. Sans meets their gaze and the fog in his head clears up a little and he suddenly realizes.

He’s staring at his soulmate.

 

* * *

 

 

You realize you’re still pointing the gun and drop it on the counter with a yelp before looking back up at the two skeleton monsters.

Both of them are dressed in black, red, and gold, like they’re going to a shitty rock concert together and wanted to match. They’ve both got big fangs and look sort of sharp all over, and it would probably be intimidating if their clothes didn’t make them look just a little bit like tryhards. The taller one is glaring at you but something about his posture is nervous. The other one, the one who just saved your ass, is staring at you with those huge, dark sockets and sweating profusely. You stare at him for a moment, entranced by his sharp, gold tooth and wondering how a skeleton can sweat, before you snap out of it.

The police! You were totally just robbed! You need to call the police!

You grab the phone by the register.

“Wait!” shouts the taller skeleton. “You can’t tell anyone!”

“What?” you ask, furrowing your eyebrows. “What are you talking about, that guy tried to rob my place of work, I gotta call the cops!”

“You can’t!!” he shrieks again, even louder this time. God, his voice is fucking ear piercing. “I command it!”

You frown at him.

“Bro,” the smaller skeleton croaks out. His voice is way deeper - kinda nice, actually - but he sounds like he might shit himself. “P’s and Q’s.”

The taller skeleton makes an exasperated noise. “Fine!” he yells at his brother. To you, he says, “ _ Please _ do not call the police.”

Your frown deepens. “I obviously have to call the police.” You gesture to the weapon on the counter. “I can’t just, like, not report it and not turn in this gun.”

“Argh! Fine! Then…” The skeleton looks around anxiously. “Please… do not… tell the police my brother used magic.”

Oh.

Right.

Monsters aren’t allowed to use magic on humans for any reason.

Even though that shorter skeleton saved you, he’d almost certainly be locked up for it. In the eyes of the law, using magic for self defense would be kind of equivalent to using a hand grenade to ward off an intruder in your home.

You glance to the back room. “The cameras,” you tell him. “They’ll check the tapes and know.”

The shorter skeleton is sweating harder now and shaking. You feel really bad for him. He looks like he might pass out. The taller one is starting to be visibly alarmed, too. 

You can’t just let this poor guy go to jail for defending you.

Your chest feels funny, kind of tight. Probably just the lingering adrenaline. You scratch at the birth mark on your chest. The two skeletons’ gazes snap to your chest and watch your hand with rapt attention, for some reason.

“Okay. I’m probably going to regret this, but here’s what we’re going to do.” They’re both still looking at your chest. You snap your fingers. “Hey, pay attention.” They look back up at your face. Okay, cool.

“The assailant forced me to delete the footage,” you say, slowly. “When we came back out, he tripped and dropped the gun, and that’s when I grabbed it.”

The taller skeleton squints at you in confusion. “That’s not what happened!”

Ugh. He’s thick. “Yes, it is,” you say, talking even slower, trying to get your point across without having to spell it out. “The gunman forced me a gunpoint to stop the cameras and delete all the footage, and then when we came back out to get the money, he dropped the gun. _ Nobody used any magic. _ ” You raise your eyebrows meaningfully.

The tall skeleton’s face smooths out. That’s so weird, how their skulls are malleable like that. “Ohhh,” he says, finally understanding. “Yes. Of course. The man made you delete the video and then he tripped and dropped the gun and no one used magic.” He turns to his brother. “Right, Sans?”

“R-right,” his brother agrees.

“Okay.” You fix both of them with a look. “Are you two sticking around to back up my story about why there’s missing evidence?”

The shorter skeleton nods. The taller one shakes his head. They exchange a look. The short one looks imploringly up at the tall one while the tall one glares down at him with his hands on his hips. Then the tall one sighs, rolls the little lights in his socket around, and they both look back at you and nod.

You nod back at them and head to the back room. You hop on the computer there, stop the camera feed, and start clicking away at the files. It’s lucky you’re one of the few employees that knows how to work the cameras and its storage system.

You can hear the two skeletons having an argument outside as you scrub the files off the computer. 

“Sans!” That shrieky voice is definitely the tall one. “That human is your -”

“Shh! Shut up, shut  _ up _ !”

“Don’t you tell me to shut up!”

“Sorry -”

“You have to do something, Sans. This is terrible news. HORRIFIC news. I can’t believe it’s a  _ human _ .”

“What, you think I’m fuckin’  _ happy  _ about it?”

“They’re disgusting -”

“Don’t fuckin’ say that ‘bout ‘em.” That sentence comes out as a low snarl with obvious malice. The tall one must be stunned at the short one’s tone, because they’re both silent for a minute.

“What a wonderful time for you to finally grow a  _ spine _ ,” says the tall one, sarcastically.

“I’m not fuckin’ jokin’ around.”

“Neither. Am. I.”

You come back out to find them staring each other down. The short one is incredibly red in the face, on top of still being sweaty. You hope he’s not overheating in that big fluffy jacket or something. “You guys good?” you ask, though the answer is obvious.

“We’re  _ fine _ ,” the short one says harshly. He immediately looks a little ashamed, turning his gaze down to stare at his feet.

You shrug it off and pick up the phone to call the police. The call is pretty short and the operator informs you that the police are on their way.

The three of you stand around awkwardly after you hang up the phone. None of you are looking at each other.

“So,” you say, trying to make conversation. “What’re your names?”

“I am the Great and Terrible Papyrus, and it is your honor to meet me,” the tall one says, crossing his arms and looking down his nose at you.

You frown at him.

“Sans,” says the short one.

“Okay… Nice to meet you guys.” You fiddle with your hands, uncomfortable. “Um, thank you for saving me earlier, Sans.”

“D… don’t mention it,” he mutters, idly scuffing his sneakers on the linoleum floor. His face is still a little red. It’s kind of cute.

Papyrus looks uncomfortable, too, and shuffles back over to the shelves he was browsing before. Sans stays in the middle of the room, peeking up at you every once and awhile.

You shamelessly stare at him while you tap your fingers on the counter. He doesn’t look like a human skeleton, not really - his skull is probably larger than your head, and what you can see of the rest of his bones look like they’re fused together in a way that a normal skeleton’s wouldn’t be.

That reminds you, you read once that kneecaps aren’t actually attached to any other bones but joined to everything with ligatures. You let your gaze slide down to the skeleton’s knees. There’s a weird sort of lump that might be a kneecap, but it’s attached directly to the leg bones above and below it. Strange.

“Quit starin’,” he grumbles.

Oops. “Sorry,” you say, looking away and out the window. You can see his reflection in the glass. He’s sneaking little glances at you. It’s cute that such a tough, scary looking monster is so unsure of himself.

“Um,” he says, awkwardly. “You, uh, you feel anythin’ funny?”

You turn to look at him directly again, furrowing your brow. That’s a weird question to ask. “Like what?”

“Like… like maybe…” The lights in his eyes shift all around the room, darting away to look at the shelves or the drink machine before returning to your face. “Like maybe somethin’ in your chest, or maybe feelin’ kinda warm all over, or like, um…” He trails off, raising his shoulders like a cat’s haunches as though he’s trying to shrink into his big jacket.

Papyrus makes an exasperated noise from the back of the room. “This is painful to listen to. I’ll just tell them,” he insists, walking back over to the counter.

“Don’t,” Sans growls.

Papyrus looks at you. “You’re my brother’s disgusting soulmate.”

“I TOLD YOU NOT TO CALL ‘EM DISGUSTIN’,” the short one yells. He immediately looks embarrassed at his own sudden outburst, flushing a bright red and glancing at you anxiously.

You take a step away from them both. You’d heard that soulmates were a real, tangible thing for monsters, but you thought they could only be soulmates with other monsters, not with humans. “That’s not possible,” you say.

Papyrus makes a tsking sound. “Ugh. Here, I’ll prove it.” He leans down, snatching his brother’s wrist and yanking it from his pocket. “Soul marks glow when you touch your soulmate.”

“Stop!” Sans shouts, trying to pry off Papyrus’s tight grip. 

Papyrus grabs your wrist too, pulling you up close to the counter before you can move away. He smashes your hand up against Sans’s awkwardly. His bones feel cold and clammy against your skin. As soon as your hands touch, his chest starts to glow a faint red. You can just barely see it through the fabric of his black shirt and peeking out over the edge of his collar. He looks down at it, his expression one of total humiliation.

“That’s nice and all,” you say, “but this could just be a magic trick. I mean, I don’t even have a soul mark.”

Papyrus gives you an incredulous look. “Yes, you do. Look down, you simpleton.”

You look down. Your chest is covered in soft indigo light. You rip your hand away from Sans’s.

“AHH!” you yell. “MY AUSTRALIA!”

Sans’s bony brow creases. “Your what?”

“My… my birth mark! It’s - that’s what I call it! Cuz it’s shaped like Australia, see?” You tug down the hem of your polo a little to give him a better look.

He looks. The corners of his toothy mouth turn up in a hesitant grin and he tugs down his collar with one hand, the other resting limply on the counter. There’s a spot on his sternum that’s darker than the rest of the bone, shaped like Australia, just like yours.

“Huh,” you say, curiously. You reach out and place your hand back on top of his across the counter, wrapping your fingers loosely around his bony palm. His chest starts to glow again, a vibrant, blinding red now that it’s unobstructed. His fingers twitch under your hand before lightly brushing up against your skin. He’s still clammy, which is gross, but the cool touch feels kind of comforting against the warmth of your palm. He lets out a long, soft sigh, the way you would while sinking into a hot bath.

You look at him, the top half of his sockets drooping down the way eyelids might, and you feel a warmth deep inside your chest.

“Oh,” you say. “This is kinda nice.”

He perks up a little. “You can feel it?”

“I feel… something?” You’re not sure if this is the feeling he was referring to earlier. “It’s faint and I didn’t feel it when we weren’t touching.”

He slumps a little, but he still looks content.

“You’re not, like… madly in love with me now or anything, are you?” you ask.

He snorts and shakes his head. “Naw. Jus’ feels like… I’m drawn to you.” He suddenly gets embarrassed again and yanks his hand back, stuffing it into his pocket and looking away. “Don’t feel like you gotta do me any favors or nothin’, cuz ya ain’t gotta. You ain’t obligated to ever see me again after this. You deleted the videos, so we’re square.”

“It’s better if we forget this ever happened, actually,” comments Papyrus, who has been watching the whole thing with restrained disgust.

“That’s boring,” you say immediately. “Don’t you want to know more about your soulmate?”

“You’re a liability,” says Papyrus.

You make an offended noise. What’s that supposed to mean?

“Human like you ain’t gonna wanna hang round a monster like me,” Sans says, scowling at the floor. “You don’t even feel the connection if we ain’t touching, so why would you care?”

“You’re joking, right? This is the most interesting thing that’s happened to me in months.” You hold out your hand. “You got a phone?”

His face goes slack and his sockets wide with surprise. “Uh, yeah, yeah I got a phone,” he says, scrambling to pull it out of his pocket and hand it to you.

You go to his contacts and plug in your info. “I’m giving you my number as an official declaration of interest in whatever the hell this is, so it’s up to you if you wanna actually do anything about it, okay?”

You hand the phone back to him and he and Papyrus both stare at you like you’ve grown a second head. He opens his mouth, about to say something else, but then the police car finally comes tearing into the parking lot, cutting the conversation short.


	2. Chapter 2

**Notes for the Chapter:**

> just fyi most of these chapters will be short and isolated to one or two scenes cuz my approach for this fic is more relaxed than usual

He doesn’t call you.

It’s been nearly three weeks and you haven’t heard from the short skeleton at all. It’s kind of disappointing - he was pretty cute and you’re curious what sort of person your soulmate is. You suppose you’re no worse off than you were before, since you don’t feel whatever instinctual connection he feels and before this you didn’t even know you _had_ a soulmate, but it’s still lame.

You guys probably would’ve had stellar sexual chemistry.

You frown at your phone as you scroll through social media, standing in the tiny spot behind the counter that’s in the gas station camera’s blind spot.

Or, wait, could he even fuck?

Damn, you won’t even get to find out if he can fuck because he won’t fucking call you!

The sound of the door’s bell jolts you out of your thoughts. A short skeleton in a fluffy jacket walks in, looking nervous. You immediately light up.

“Aw, hey, it’s my guardian angel!” you exclaim, stuffing your phone in your pocket and moving closer to the counter. “I was just thinking about you!”

Sans stops in his tracks, looking at you as his face goes bright red. His sockets are wide and the bone underneath looks a little darker, like he hasn’t been sleeping well. He shakes his head like he’s got something stuck in his skull and he’s trying to get it out, then glares at you, snarling. The effect would probably be menacing if he wasn’t still blushing. “I - I ain’t a fuckin’ angel! Don’t call me that!”

You hum thoughtfully and try not to laugh in his face. “You look like one to me.”

You don’t miss the surprise flash across his face before he wrangles his expression back into the glower. “Then you need yer fuckin’ eyes checked,” he grumbles. “I look more like the devil than an angel, sweetheart.”

“Lucifer is just a fallen angel,” you tell him.

He sputters and stomps towards the back of the store. You watch him carefully. He feigns looking at the shelves for a little bit before trying to sneakily take a peek at you. He apparently wasn’t expecting you to be watching him, because he looks like he’s about to shit his pants when he meets your gaze and he quickly looks back down.

“You never called me,” you yell across the store.

“You don’t actually want me to,” he yells back, gnashing his sharp teeth like a cartoon shark. “Yer just fuckin’ with me!”

You cross your arms and frown at him. “I literally explicitly said I was interested in getting to know you.”

“You said it was up to me to do anything about it! So I didn’t!”

You’re thrown off a little bit by that. “Well… I didn’t expect you to _actually_ not do anything!”

He stares at you with a funny look on his face. His brow is furrowed and the bone above his nasal passage is furrowed. “I’m a _monster_ ,” he says, spreading his arms out as if to give you a better look.

“Okay,” you say, mimicking his pose. “And I’m a human. What’s the issue here?”

“You’re a lil freak, ya know that?” he says, the corners of his mouth turned sharply down. “Doesn’t anything scare you? You’re not scared of me bein’ a monster, you got over a guy stickin’ a gun in yer face after like two minutes… what is _wrong_ with you?”

You shrug. “This place gets robbed like three times a year because this is a shitty neighborhood. And you’re really not all that scary.” Despite his surly demeanor he doesn’t really strike you as the type of person to hurt someone for fun. You get the feeling his scary monster act is mostly for show.

“I’m a _monster_ with _sharp teeth_ and _claws_ and _magic_ ,” he says, walking closer to the counter and raising his hands so you can see how the bones of his fingers - far thicker than human phalanges - taper into sharp points. “You’re a soft, fleshy human. My teeth could sink into your neck like you’re made of butter. That doesn’t _bother_ you?”

You probably shouldn’t say what you’re about to say, but… you can’t help yourself.

“Kinky,” you joke, grinning crookedly at him.

His face goes entirely red and starts glowing like the taillight of a car. You laugh, long and loud.

“Look,” you say, a little more seriously, once the giggles subside. “I’ve basically offered myself on a silver platter to you. If you really wanted to eat me, in the literal sense and not the sexy way, you would’ve done it by now. Instead, you come in here to take little sneaky peeks at me like you’ve got a schoolboy crush and warn me about how definitely, totally scary you are.” You lean over the counter. “So no, it doesn’t bother me.”

He stares at you for a moment, his face blank and red. Slowly, his mouth twitches upwards into a grin. “So you’re just a fuckin’ weirdo, huh? Is that it?” He comes closer, puts his palms on the counter and leans in, getting close to your face. “You freak. I bet you _want_ me to bite that pretty little neck and mark up your skin with my claws.”

Your face is warm but you’re sure you must be grinning wildly. Your life is usually so fucking boring but this is so fucking _interesting_. You put your hands down on the counter, deliberately resting some of your fingers on top of his. Both your chests light up with color and his expression falters, his sockets drooping into half moons and the lights inside going hazy as he looks at you.

“Why don’t you find out?” you challenge him.

He growls and it sounds like it’s rumbling deep within a throat he doesn’t have. Fuck, that’s kinda hot. He grits his teeth, inching his face closer to yours. You’re practically within kissing distance, nearly your entire vision full of those deep, black sockets and the little red lights.

“Damn,” he mutters, dreamily. “I wanna tear off that stupid uniform and throw you on the counter and find out what makes you purr. Wanna mark you up and keep you in my bed all night so ya smell like me, so everyone knows yer _my_ mate. Wanna hold you close and feel how warm you are and feel yer hands on me, wanna listen to that laugh again and make you feel good and find out what you like to eat for breakfast in the morning after and -”

He stops, cutting himself off and looking alarmed at his own words, then yanks his hands away from yours and stumbles backwards.

You pull back too. That took a weird turn from carnal and sexy into romantic and domestic. Your stomach is twisting and you giggle a little, nervously. “Holy shit, dude,” you say.

He looks wholly embarrassed, looking down at the floor and shoving his hands in his pockets. “‘S your fuckin’ fault. You touched me.” His face is red again, his brow creased. “The connection is more intense if we’re touchin’. Makes my head go all stupid. I don’t say that kinda crap usually.”

You feel just a little bad. He’s practically pouting and he’s lost all the steam he built up. “But you feel it even we’re not touching, right?”

He nods. “Makes me think about you and wanna get to know you, be close to you,” he says, sounding frustrated. “But it ain’t gonna work out so I just better get used to feelin’ that way.”

“How do you know if it’ll work out or not?” you ask.

He shrugs.

“Look,” you say, sighing. “If it’ll make you feel worse if we do try seeing each other and it doesn’t work, I get why you wouldn’t wanna try at all. But _I_ wanna try. I think you’re interesting and cute.”

He makes an odd, strangled noise at being called cute. “Whatever,” he says. “I’ll.. think about it.”

He storms out without buying anything.

He texts you that night and asks if you’d like to get dinner.


	3. Chapter 3

The dinner date, if you can even call it that, is incredibly awkward.

You go to a diner - your suggestion, actually, because you like their greasy food and their coffee - and sit uncomfortably across from each other in a booth. You have to be careful not to make direct skin-to-bone contact, because if you do, any humans watching might think he’s using magic on you and freak out and any monsters would be startled to see a human with a soul mark.

When Sans isn’t sitting there silently and glowering at his food, he gruffly asks you strange questions the whole time. Stuff like, “If ya got into a fight in a dark alley alone at night, what would you do?” Or, “If there ain’t nothin’ good in the fridge, do you suck it up and eat somethin’ you don’t really want, or do you order in?” Or, “If someone paid you a hundred bucks to scrape some gum offa the bottom of this table and chew it, would ya do it?”

“Okay,” you say, setting down the mug of coffee that you shouldn’t be drinking this late at night. “What’s up with the weird questions?”

He looks up from his current task of stabbing his eggs to death, his cheekbones tinged with red. “Whattya mean?”

“These are not normal date questions,” you tell him, but then you pause, a thought occurring to you. “At least, they’re not for humans. Is this what monsters do on dates? Ask weird hypothetical questions?”

He looks away, scowling. “How am I supposed to know? I don’t fuckin’ date.”

You quirk a brow at him. “Not at all?”

He lets out a frustrated noise. “Don’t give me that look,” he grumbles. “I ain’t a fuckin’ virgin, I _hook up_ , I don’t _date_ , most monsters don’t. Only reason I’m doin’ this with is you is ‘cuz…” He stops, looking around warily, as though he’s afraid of someone listening in, although the diner is mostly empty. “‘Cuz of that,” he finishes lamely, nodding at your chest, at your soul mark.

You hum thoughtfully. “If that’s the issue, we can just do that.”

“Do what?” he asks. He goes to take a sip of his drink.

“Hook up.”

He chokes, nearly spitting up his drink. Weird that the food seems to go somewhere when it goes behind his teeth, but it’s obviously not going down his throat because he doesn’t have one.

“No!” he shouts, loud enough that the waitress behind the counter gives him a funny look.

“Why not? If you don’t like dating…”

“Cuz yer supposed to be… you…” He trails off, unable to finish the thought. He looks legitimately kind of upset, his brow turned up in the middle and his mouth frowning instead of scowling.

“Hey,” you say softly. “Chill. It’s cool. It was just a suggestion.”

He still looks uncomfortable, but he relaxes a little.

“You never answered the question,” you say, steering the conversation back on track. “Why the weird questions?”

He shrugs. “Didn’t wanna ask ya the same stupid stuff a million guys have probably already asked ya before.”

You laugh a little at that. “Okay, how about I try asking something? What do you do for fun?”

“Um.” He almost looks surprised and bashful that you want to know stuff about him. “V… video games.”

“Cool,” you say. “I play sometimes. What kind do you like?”

He perks up a little bit. “Well, I’ve just been guessin’ and what I might like when I buy shit cuz we didn’t have any of this shit Underground, but I’ve been playing a lot of shooters and…”

* * *

 

Later, as the two of you leave the diner, you ask him to walk you home.

His face twists up a little, the bone above his nasal cavity wrinkling. “Ain’t this what humans do at the end of a date to show they wanna fuck?”

Ouch. The way he said that kinda stings. You thought he found you attractive based on the flirting earlier in the day, but maybe that was only the soul bond talking. “Woah, dude, no need to spare my feelings, I guess.”

His expression morphs into embarrassment. “It ain’t that!” He looks away. “It’s just… I’m tryin’ pretty hard not to fuck this up.”

“If you’re worried that I’m trying to turn this into nothing more than a hookup,” you say, guessing at the reason for his discomfort, “I’m not. I’m just giving you options. If you walk me back, we can fool around or we can just play video games. Or we can cut the date off now. None of those choices means the date is a total bust.”

“That…” He seems to be struggling with something. “I’m… worried…” he pauses, cringing at his word choice, “that if we touch I’m gonna say some stupid shit. And you’re gonna freak the fuck out. Cuz… you don’t feel it like I do.”

You roll your eyes. “I’m not gonna freak out.”

He eyes you warily, searching your face. “You’re gonna ask me a bunch of fuckin’ annoying questions about my _feelings_ and about souls ‘n shit.”

You grin a little. “Okay, I’m probably gonna do that. So sue me, I’m a curious soul.”

“Literally,” he says. He’s grumbling but he seems to have relaxed a little.

“Huh?”

“Uh. Your soul’s core trait is curiosity.”

You furrow your brow. “How can you tell?”

“You glow that one shade of purple,” he says, like that explains it.

You just give him your best confused look.

The lights roll in his sockets. “Fuck, see, yer already doing it, makin’ me explain all this shit. Can we just start walkin’ to your place and I’ll explain on the way? We look like idiots standin’ out here arguing.”

You beam at him and he turns red.

* * *

 

The two of you step into your apartment. Sans, in the middle of some explanation about distinguishing secondary core traits, is so caught up in talking that he doesn’t notice where he is until you’ve already locked the door. He cuts off suddenly, looking around your place.

“It’s not much, but it’s home,” you tell him. He doesn’t move to take off his sneakers even though you’ve already taken your shoes off.. “Hey, shoes off indoors, buddy.”

He seems to snap out of it and slides them off without undoing the loosely tied laces.

“So,” you say. “You wanna play something?”

“Uh.” He shoots you a grin, a little cheekily. His face is turning red, just a little. “Actually, now that we’re here, all I can think about is jumping your _bones_.”

“Oh, shit, really?” you ask, a little excited. You’d maybe been wondering how that would work and you want to find out. “Do you wanna go straight to the bedroom, or we can chill for a minute and watch trash TV, or -” You cut off, noticing he looks disappointed. “What’s wrong?”

“Not even a polite chuckle, huh?” he says, ducking his head, like he’s sulking a little.

You frown. “What? What’re you… oh my God.” You sigh as you finally notice his play on words. “Was that supposed to be a _joke_?”

He averts his gaze, looking legitimately kind of crushed.

You feel a little bad. He’s fun when he’s confident and comfortable, and you just bummed him out. He looked really excited to joke around with you. You sincerely, genuinely don’t like puns, but…

You sigh loudly. “Puns are stupid, but I’ll put up with them,” you say. “Only because you’re gonna take me to the… _bone_ zone.”

His face lights up. It’s the biggest, most sincere smile you’ve ever seen on him. “Heh heh heh… Did you just…”

“Don’t make me regret it,” you warn him, but you’re grinning too. It’s cute that the supposedly mean, tough skeleton monster is this excited over wordplay.

“Aw,” he says, his grin turning into a smirk. “Am I getting… under your skin?”

You groan. “No, we are not doing this. I made one whole pun for you, we’re not having a pun-off.”

He moves closer to you, backing you against the door. His sockets are half-moons again, his eyelights zeroed in on you, like earlier at the gas station. When your back bumps against the door, he slams his hands against the wood on either side of you, boxing you in.

“What’s the matter?” he asks, his voice so low that it sends a jolt down your spine. “You that eager to get a second skeleton inside of ya?”

“Jesus _Christ_ ,” you say, legitimately a little pissed that you’re aroused while he’s he’s doing this. “Will you shut up and find something better to do with that big mouth of yours?”

He laughs, a deep, rumbling sound that gives you another jolt. “Okay, doll.” He leans in and scrapes his sharp teeth against the skin of your neck, quickly, so that your chest and his barely flicker with the soul mark’s light before he pulls away. “Was I right, before? You want me to bite this pretty neck?”

You nod dumbly and he lightly nips at you once, then twice, then a third time, testing you, giving you time to decide you don’t want this and tell him to stop.

You don’t. Instead, you let out a soft, pleading moan, arching your back so that your breasts brush against his chest, and he breaks, shoving one hand up your shirt, his cold bones on the warm skin of your stomach, and sinks his teeth into the meat between your neck and shoulder. Your birthmark lights up like a neon sign.

He doesn’t bite you too hard, careful with the pressure of his sharp teeth, but he’s probably broken skin just a little with his longest teeth. You hiss at the pain, then gasp as something wet and soft presses against the sore skin between his upper and lower teeth.

He groans, sounding satisfied with your reaction. His hands are groping at your hips now, tentatively exploring under the waistband of your pants. He releases his teeth from your neck, running that soft, wet thing over the bite mark, and dimly, you realize that it’s a tongue.

“Damn, you’re so fuckin’ soft ‘n warm,” he mutters, pulling your hips closer to him. To your surprise, you can tell he’s definitely packing _something_ when you bump up against his pelvis.

“Bed,” you say, barely managing to get the word out. He grunts and doesn’t move, just stands there with his bony face pressed up against your neck, until you put your palm on his shoulder and nudge him in the right direction.

Finally he stumbles backwards, dragging you with him, huffing hot air through his nasal cavity. You have to steer him a little, because he absolutely refuses to stop touching you and keeps nipping at your neck, but eventually the two of you make it to your bedroom and he shoves you onto the bed. He pushes up your shirt, gestures for you to take it off, before working on unbuttoning your pants.

You end up entirely nude pretty quickly, your undergarments thrown off somewhere, and you adjust your position on the bed, getting comfortable while Sans climbs on top of you.

“Hey,” you say, squirming a little bit as he looks down at you. The lights in his eyes are hazy again, and his gaze is blatantly roaming your body. “You’re not doing this fully clothed, are you?”

He looks you in the eye, furrowing his brow slowly. “You want me to take it off?”

You laugh a little. “You’re wearing a massive jacket, I can barely touch you.”

He sits upright for a second to pull his jacket off, then moves to take off his shirt, but hesitates. He seems uncomfortable, and you wonder if he’s insecure about how he looks for some reason. “Can I leave the rest on?” he asks.

“Sure, if you want to,” you say, resisting the urge to cover yourself. “Being the only one naked makes me a little self-conscious, but it’s not a big deal.”

“Shut up, s’not like you have anything to worry about,” he says, leaning over you again. “You look hot as hell.”

He presses his face to yours in something resembling a kiss. You close your eyes, unsure of what to do when confronted with a row of massive teeth, but as soon as you part your lips, his mouth opens and you feel his tongue slip into your mouth. It’s weirdly featureless - it doesn’t have bumpy tastebuds, or a ridge on the underside of it - but it’s not unpleasant. He toys with your tongue, exploring your mouth, as he slips a hand under you, keeping it on your lower back. His legs are between yours, his knees nudging your thighs apart as you cling to his shirt.

He runs a hand down your side, over your hip and to your thigh, grabbing it roughly and probably leaving indents in your skin with those pointy phalanges. Once he’s satisfied with feeling up your thigh, he shifts slightly, giving himself room to slip his hand between your legs. To your relief, his hands aren’t so cold now that they’re warmed up by your body. He prods around gently, careful not to scrape you, sliding two fingers between the lips and briefly over your clit before finding your entrance and pressing inside of you. You whimper at the light stretching feeling, clenching around his fingers.

“Fuck, you’re sopping wet,” he says, pulling away from the kiss and pulling his fingers out. He looks at his hand, experimentally separating his fingers and watching how your wetness clings to them. “You little freak. We’ve barely done anything yet.”

You can’t help it. You’ve had a fair amount of sex, but not with monsters. A lot of this is new, different, exciting. You can’t think of anything clever or especially raunchy to say, so you just say, “Please fuck me.”

His sockets go wide for a second before they lower into half moons again and he grins. “Fuck,” he swears, shoving his fingers back inside of you, scissoring them before starting to pump in and out. “I’m gettin’ to it. Slow your fuckin’ roll.” He pulls his other hand out from underneath you, groping at your breasts, running his thumb over your nipple lightly until it hardens. “I wanna… wanna feel you. Figure out what you like before I go shovin’ my stupid dick in ya.”

He slows the pace of his fingers and you buck, whining, so he goes faster again. He tugs on your nipple, hard, and you yelp. He furrows his brow, switches to rolling your nipple between his fingers and pinching it roughly, and seems satisfied when your head lolls to the side and you let out little gasps. He watches your face carefully, focused on your reactions.

“I didn’t expect you to be so methodical,” you say, in between pants.

He brushes his thumb over your clit, growling hungrily when you roll your hips against his hand. “Ain’t usually like this, but this… this ain’t just some random fuck.” His hand is at your throat now, lightly wrapped around it, and he lets out a shaky puff of air when he feels you swallow hard. “It’s - yer my fuckin’ soulmate. My forever mate.”

Your gut coils pleasantly at that, but you don’t know why. You don’t know him that well yet.

He seems to suddenly be getting emotional. He blinks deliberately, shaking his head, his brow creased and his mouth in a frown. He withdraws his fingers from your cunt. “Jus’ wish… you felt it like I do. The bond, or whatever. Fuck me, I wanna make ya feel good. I wanna know everything about ya, I wanna know what makes ya cum, how ya like to be held after, what you like for… shit!”

He grits his teeth. Droplets of some kind of liquid are collecting in the corner of his sockets. They might be red in color, but it’s hard to tell - both your chests are glowing so brightly by now that everything looks either red, deep purple, or some shade in between.

“See? What’d I fuckin’ tell ya,” he grumbles, upset. “I told you I’d say some dumbass stupid shit.”

You reach out, touching his cheekbone. He flinches, then melts into the touch and allows you to wipe away the liquid - tears, you suppose. It doesn’t make any sense that he can cry, but he’s got a tongue and a dick, so you guess that logic doesn’t really apply here.

“I don’t think it’s stupid,” you tell him. “It’s sweet. It’s nice to hear you say what you’re thinking and feeling. I wish I felt it more, too. The connection you have to me, I mean.”

He stares at you for a minute.

Then he buries his face in your neck, nipping at your skin as he shoves his pants down. You can feel his cock prodding at your entrance, one of his arms next to your head for balance, the other grabbing your hip.

“I wanna fuck you so bad,” he says, and you immediately buck up against his cock, causing the head to slip between the lips of your pussy. He hisses, involuntarily pressing against you for a split second before drawing back. “Fucking _impatient_ , fuck!! Will you hold on a second?! I’m tryin’ to say somethin’!”

“Sorry,” you say, going still.

“I wanna fuck you, but I jus’ know the bond is gonna make me say some stupid -” he cuts off, tries again - “some crazy mushy shit. I mean, real fuckin’ crazy. You hafta promise to tell me to stop if ya get freaked out.”

“Okay,” you tell him. “I can do that.”

“Okay,” he says, huffing out a breath and pressing his dick inside of you.

You inhale sharply, spreading your legs a little more. He’s _wide_ , practically stretching you to your limit. It stings just a little, but fuck, the burning almost makes it better. He’s pushing in slowly, but you roll your hips, trying to get him to fill you as you clutch the sheets. “Fuck, Sans, holy shit,” you curse, sucking in breaths through your teeth.

He groans in response, nearly collapsing on top of you. He gnashes his teeth, snapping his hips forward so that he’s fully inside you, his pelvis pressed up against your lips. “Oh, fuck, you’re so fucking hot - oh shit - my soulmate, my mate, _mine…_ ”

He fucking snarls, pulling out and slamming back inside you, his hand moving from your hip to your breast to play with one of nipples again. He’s babbling, his teeth scraping your neck as he talks, and you’re so blissed out as he fills you up over and over that you only catch snippets of what he’s saying.

“ - I’ll protect you forever and ever and everyone’s gonna know you’re mine - ”

“ - I’ll give it to you, I’ll fuck ya so good you’ll wanna always be on my fuckin’ dick, always smell like me - ”

“ - throw you on the table and fuck you in that stupid diner with everyone watching, just ‘cuz ya smiled at me like I’m worth a damn - ”

“ - didn’t think fate was real before this but now I do ‘cuz everythin’ you do makes me wanna fall in love with ya - ”

He presses his body against yours, his ribs pushed up against your breasts so that you can feel them through his shirt. He humps you like a wild animal, in a total frenzy, forcing you open faster than you can stretch, his pelvis rubbing up against your clit and his fingers grope you aimlessly as he loses himself in the feeling of your cunt clenching around his cock, and his desperate voice is in your ear moaning your name -

You cum hard, convulsing and moaning a broken, “Oh, fuuuuck.” You instinctively curl around him, your arms circling his back even though his spiky spine is digging into you, your legs hooking around his pelvis, effectively trapping him inside you as your pussy clenches in time with the convulsions shaking your body. He lets out a strangled cry, rolling his hips and cumming inside you.

You come down from the high, going slack underneath him, and he pulls out before rolling off of you to the side.

“Holy shit,” you pant, trying to catch your breath.

Sans is already adjusting his pants. “That - that didn’t freak you out?”

“I mean,” you say, turning to him and trying to ignore the cum cooling between your legs. “A lot of that was kind of heavy, I think, but it was also just like, amped of versions of what I’m feeling.”

He looks shocked. “What?”

“I mean, all that junk about wanting to fuck me and protect me and falling for me or whatever…” You sling an arm over his body, and a leg over his leg. “I’m not quite at your level yet, but obviously I’m attracted to you and the more I learn about you, the more I like you, so maybe I’ll get there.”

The light in his chest pulsates brighter for a second. “You’re serious?” he asks, turning and slinking his arms around you. He seems twitchy, unsure of what to do with his hands, like he’s never really cuddled before.

“I’m not making any promises,” you tell him. You rub circles into his shoulder blade with one hand, and he copies the motion with one of his hands on your back. “Shit happens. This could go horribly wrong with no warning. But like… we’re soulmates for a reason, right?”

His eyelights are so fuzzy, you can’t even tell where the edges are. “Right,” he agrees, before burying his face in your neck again and promptly falling asleep.

**Author's Note:**

> this is just a goofy little thing i’m doing for fun on the side when i need a break from my longer sans fic. please expect it to rapidly devolve into vignettes and smut
> 
> also apologies if the characters arent what you expect from this au its hard for me to tell what the canon is haha


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